1. Field of the Invention
The present invention relates to coil strapped nails, as well as a nailing device and nail coil for use in a nailing device. More particularly, the invention relates to a coil strap with steel nails, which are integrally connected by means of at least two wires, as well as a nail strapped coil and a nailing device.
2. Description of the Related Technology
Nailing devices, which are powered by compressed air, gas, electrical energy or by hand and which use nails stored in a magazine are known in the art. Typically a nailing magazine contains up to 140 parallel-aligned nails, which are connected, e.g. welded, to each other by means of a wire at the nail shafts. The ductility of the wire permits a wrapping of the nail strap into a coil, in which shape it is used in the respective nailing device. Current designs feature connecting wires made of soft, unalloyed metals, which permit easy coiling and welding of the wire-nail connection. One drawback of these devices is that the use of such a design in a nailing device is difficult if not impossible, as the hammer action causes a reduction of the nail pitch. The nails, furthermore, incline towards the magazine center. When in use, repeated malfunctions of the nailing device occur as the nails, as mentioned before, jam due to twisting, reduction of nail pitch and excessive inclination of the nails by means of the hammer action. These malfunctions are particularly evident, when the nail strap is nearly used up and the remaining nail strap is unsupported inside the magazine. These disadvantages have to be eliminated.
Extensive research has been devoted to the connection between wire and nail shaft (where an unintentional reduction of nail pitch and inclining of the nails was to be avoided). However, there remains a need for a trouble free separation of nail and wire within the nailing device during hammer action, while ensuring a proper wire-nail-weld.
Accordingly, an object of the present invention is to provide coil strapped nails, which oppose a twisting, misaligning of nails and which ensures a reliable separation of nail from wire within the nailing device by means of the hammer action, thus enabling trouble free and fast work. It is also an object of the invention to design the nail strap coil and the nailing device in such way as to prevent a jamming of the nail strap.
According to one aspect of the invention, in order to avoid misalignment of nails within the nailing device and subsequent jamming of the nailing device, it is proposed to use a quenched and tempered metal. This offers the advantage that the wires can be hardened, which greatly influences the ductility of the wires, while ensuring reliable positioning of the nails of the nail strap during drive-in.
With respective tensile strength of the wire, the problem is solved for nails 14 to 25 mm long and a shaft diameter of 2 to 3 mm, preferably 2.5 mm in that the wires are pitched at 6.5 to 7.5 mm, preferably 7 mm, to each other. At the predetermined nail length and pitch claimed by this invention, only a minimal deviation of the nail pitch from the desired position is possible, which prevents jamming of the nailing device. At the same time, the pitch between nails is short enough for the impact element of the nailing device to impact on both connecting points of wire to nail, thus ensuring a reliable separation of the nail from the wires.
According to a preferred embodiment, nails with heads are preferable. The wire nearer the head is 9 to 11 mm, preferably 10 mm, distant from head to connecting point on the shaft. This distance of the wire nearer the head to the head ensures a trouble free separation of the nail from the wires. The distance of the wire nearer the head is generally equal to the diameter of the head. In an exemplary embodiment, the nail strap contains 70 to 85 nails, preferably 80 nails, which avoids a too frequent changing of the nailing device, while ensuring a usable size and weight of the nail magazine. The size of the coil strap is limited by the weight of the nail strap and by the size of the magazine.
As is known, nails are preferably inclined by 15 degrees to the vertical with the wires being in horizontal position. As described previously, quenched and tempered connecting wires are preferred, which keep the nails in a somewhat flexible position, thus avoiding malfunction. This feature is however not sufficient in all cases. Furthermore it may be necessary to use ordinary coil strapped nails without quenched and tempered wires.
According to the invention, it is furthermore envisaged to use a wrapping sleeve inside the coil where the outside diameter of the wrapping sleeve is identical to the inside diameter of the coil and where the cylindrical face of the wrapping sleeve is in contact with the nail shafts or wires respectively of the inner coillage, but with clearance for the nail heads. One design features a cylindrical wrapping sleeve where a distance from the magazine floor is maintained, allowing clearance for the nail heads of the inner coillage, which protrude inwards and underneath the wrapping sleeve. A different design features a wrapping sleeve with a groove suitable to accommodate the nail heads. Further features are determined by their application and can be derived from the description and drawings.
The present invention is also directed to nail strapped coils for application in such a nailing device where the coil displays the described features.